Sufficient hydration is important for replacing bodily fluids during periods of aerobic activity, such as during cycling. A person engaged in aerobic activity could stop the aerobic activity and take a drink, such as at aid stations. However, this disrupts the aerobic activity and is not well suited for events like competitive cycling races.
It is desirable to make replenishment fluid available without the need to slow or stop aerobic activity. Water bottles carried by persons engaged in aerobic activity represent an attempt to overcome the problems associated with aid stations. However, water bottles can be awkwardly shaped and at least one hand is required for as long as one is drinking from the water bottle. Therefore, the use of water bottles can present safety hazards to cyclists and other active individuals.
In an attempt to overcome the deficiencies of water bottles, hydration systems have been developed that include a flexible reservoir for holding fluid, a flexible tube for conveying the fluid from the reservoir to the person engaged in aerobic activity, and a valve, such as a mouth operated “bite valve,” attached to the end of the tube. In the case of a bite valve, when it is desired to replenish fluids, the person engaged in aerobic activity places the outlet of the valve in his or her mouth and bites down on a flexible sheath. The sheath deforms and is taken out of sealing engagement with an internal stem, and fluid from the reservoir flows into the person's mouth. However, bite valves can be subject to wear as the flexible portion (typically made of polymeric material) tends to weaken over extended use. If weakened, the valves may experience difficulty in maintaining a closed position when the biting force is removed, and thus may leak. Furthermore, a typical bite valve cannot be adjusted to an “always open” position to allow for free flow through the valve.